1. Field of the Invention
The present invention relates to a technique for fabricating an integrated circuit device, more particularly, to a semiconductor device and fabricating method thereof.
2. Description of Related Art
In general, a number of devices are used in an integrated circuit to produce the desired circuit functions. These devices may include bipolar and metal-oxide-semiconductor field effect transistors, junction diodes, resistors and capacitors. With the rapid development of electronic products, the demand for integrated circuits (IC) having more desirable properties like higher capacitance, higher operating efficiency and smaller volume increases.
For example, one important requirement of a capacitor is to have a high degree of accuracy even in the absence of an applied voltage. In other words, the capacitor must have a very good charge storage capacity and the loss of electric charges must be kept to a minimum. One commonly used capacitor in integrated circuits is the polysilicon-insulator-polysilicon (PIP) capacitor.
When the PIP capacitors and the transistor devices need to be integrated in an integrated circuit process, an additional masking process is introduced to pattern the polysilicon layer and define the upper electrode of the PIP capacitor. Furthermore, if a silicide process needs to be performed, a block layer is formed over that portion of the areas not requiring any silicide reaction. Therefore, an additional masking process is required to fabricate the block layer so that the covered areas are defined. In particular, because the area already covered by the block layer can prevent a silicide reaction, there is no need for additional film layers. The block layer is also called a self-aligned salicide block (SAB) layer.
Since forming the PIP capacitors increases the fabrication of an integrated circuit device by at least two additional masking processes, for example, the patterning of the polysilicon layer and the self-aligned silicide block layer, the process is more complicated and the cost of production is higher.
In addition, a few U.S. patents have also disclosed some of the techniques related to the foregoing discussion, for example, U.S. Pat. No. 6,218,234 and U.S. Pat. No. 5,434,098. Thus, the articles disclosed in these patents can be used as reference material in the present invention.